It’s a terrible setback for Carwin, who hasn’t competed since June 2011 due to a series of neck and back surgeries, and was already forced to drop out of a fight with Nelson at UFC 125. Carwin hasn’t won a fight since his knockout of Frank Mir in March 2010, and at age 37, his competitive days are running out. There’s no word yet on the severity of Shane’s injury, or when he might return to action.

And by the way, this means that five of the last seven U.S. seasons of TUF — 10, 11, 13, 15, and now 16 — as well as one of the two international seasons (TUF Brazil), have ended with the coaches’ fight being canceled or delayed. Spooky. We’ll let you know when Roy Nelson picks up his replacement opponent. Our suggestion: How about Pat Barry, who’s already booked on the card against Shane Del Rosario?

And hey, speaking of UFC stars who have to pull out of fights next month due to knee injuries…